Sync localStorage when exit context

Sync localStorage when exit context

[Title] Sync localStorage when exit context
[Issue#] N_SE-52462, VPSS-1163
[Problem] localStorage is not saved when the app exits right after assignment
[Cause] Saving items on local storage is done asynchronously by scheduling it. But on this case, there is no enough time to store items asynchronously.
[Solution] Force sync localStorage before exit context

Change-Id: I6f4a995104d2cf44f727c9968a7e2a44e2d7380b